Drinking too much water?
by Laura Du Pre, Veterinary Surgeon
Does it seem your dog or cat is drinking too much water? Have you noticed your cat suddenly drinking from the tap or your dog drinking out of the toilet? The cause could be a significant underlying disease.
In this post, Laura Du Pre, Veterinary Surgeon and Clinical Director of Calder Vets, looks at how to identify a problem, and how to treat any potential issues.
What is a normal amount for a dog or cat to drink?
Textbooks define normal water intake as 1-2ml per kilogram of bodyweight per hour (equivalent to approximately 25-50ml/kg/24hrs). A Westie would be expected to drink approximately 480ml (just under a pint) in 24 hours. There is some variation between individuals, dependent on the amount of water taken in with their food and water lost through exercise and panting.
Polydipsia (increased drinking) is defined as more than 100ml per kg per day, but some pets may have noticeable increased drinking at a lesser amount . Intake higher than 50ml/kg/ in 24hrs is cause for concern. Over 100ml/kg/24hrs is a serious problem. Polyuria refers to an abnormally high urine production.
Why might my pet be drinking too much water?
Balance is tightly controlled by the body through regulation of water intake and water loss in the urine. Lack of water intake or excessive water loss causes the pituitary gland in the brain to release “anti-diuretic hormone” (ADH). This signals the kidneys to conserve water and to concentrate the urine. The thirst center in the brain is triggered to stimulate drinking.
The most common causes of drinking too much water
- Kidney (renal) dysfunction
- Liver (hepatic) disease
- Diabetes mellitus (“sugar diabetes”)
- Diabetes insipidus (“water diabetes”)
- Hyperthyroidism (over active thyroid) in cats
- Pyometra, an infection of the uterus (“womb”) in unspayed animals
- Cushing’s disease, an overproduction of natural steroid, cortisol, by the adrenal glands
- Addison’s disease, reduced steroid production by the adrenal glands
- Urinary tract infections
- High calcium levels, sometimes associated with cancer
- Behavioral issues as pets become psychologically obsessed with drinking excessive amounts of water (psychogenic polydipsia)
- Compensatory polydipsia- losses after vomiting or diarrhea
It can be helpful to measure their water intake over a 24 hour period. Pass this information on to your vet, along with a fresh urine sample, ideally collected first thing in the morning.
Finding a diagnosis
Less serious cases will be relatively straight forward to diagnose and require minimal testing. (Such as water intake measurement, a urine sample and a blood test). Others can be time-consuming, frustrating and costly.
Your vet may recommend a series of tests and investigations, starting with:
- Urinalysis to check how concentrated the urine is and to check for the presence of glucose and signs of infection.
- A 24 hour water intake measurement to confirm polydipsia and define the degree of polydipsia.
- A complete blood count and serum biochemistry to check their liver, kidneys, blood glucose and thyroid levels. This may include additional specific blood tests of hormone function.
The Vets may need to do X-rays and an ultrasound of your pet’s abdomen to look more closely at their liver, kidneys and adrenal glands to reach a diagnosis.
What treatments are available and what is the prognosis?
The treatment for drinking too much water in dogs and cats really depends on the underlying cause.
- Diabetes, your pet would require daily insulin injections.
- Cushing’s disease. Daily medication to control the signs.
- Chronic kidney disease. Treatment aimed at maintaining kidney health and quality of life include dietary modification, medication and allowing free access to water.
The prognosis ultimately depends on the diagnosis. It can vary from very good to very poor. An early diagnosis can influence a more favorable outcome. Increased drinking is an important sign and an indication for the need to investigate.
Please contact your local vets if you have any concerns about your pet’s drinking habits and never restrict your pet’s water intake.
